Denon AVR3300 - Resetting activated Protection Circuit

SOURCE: Denon AVR-1508 Receiver problems - cuts off and goes into protect mode

Usually when the unit runs for a while before shutting down there are two possibilities:

1) There is a small amount of DC current present that effectively heats up the speaker coils enough to cause a temporary short circuit that kicks in the protect circuit.
2) The output transistors or bias transistors are sensitive to heat and breaking down again causing the protect circuit to kick in.

A few experiments to try:

1) Does the time to shutdown change depending upon the volume level?
2) Is there any background noise coming from the speakers? Listen to a blank tape for example. Is there a hum or any other noise that you would not normally expect?
3) If you have a DC voltmeter, check for any voltage between the speaker lines.

Update this and we'll try to narrow this down.

Dan

Posted on Aug 19, 2008

SOURCE: Denon AVR-2307 Protection Circuit Activated permenantly

The speakers are 4 ohm speakers, a guy on another chat site sent me a link to the impedance curves http://www.audioholics.com/reviews/s...t-v2-fs/page-4

He agreed to that there was a mismatch as the unit has plenty of fresh air around it, plus all the speaker cables have been tested and installed correctly.

So, off to the store where I got it from tomorrow.

Posted on Jan 04, 2009

SOURCE: amp comes on and goes

Protection is usually a sign of overheating or something is wrong at the power amplifier's output.

Theory: Protection is a delay and sometimes an internal test to allow the electronics to stabilize during power up before they are allowed to interact with the speakers. The most common cause of it remaining ON is that a speaker cable pair is shorted. Some isolation is required...

1. Turn the Power OFF.
2. Disconnect each set of the speaker wires that are directly attached to the receiver. Mark them so you remember where each one went. pay special attention to which conductor is on "+" or "POS" and which is on "-", "COM" or "Ground". You may elect to disconnect them one pair at a time if your sytem is complex and you don't want to lose track of where things were.

Turn the Power ON. Is the "Protect" indication gone from the display?
--------------------
If YES, you have a shorted speaker wire or speaker. To isolate the specific cause:

1. Turn the Power OFF.
2. Attach ONE speaker wire pair at a time and test it by turning the Receiver ON. When the "Protect" light returns you have isolated at least one of the cause(s). Disconnect the defective speaker cable and continue isolation of all speaker cables. Visually examine the cable at both ends for frayed wires that could touch each other or contact metal on the receiver or other objects.

To isolate further within the cable/speaker pair - disconnect the speaker end of the cable on the failing path. Try another cable that you know works, or at least one that doesn't cause Protection to stay on.

If you're electrically savvy and have a Digital Volt/Ohm Meter you can troubleshoot the short(s) with it.
-------------------------

If NO, there is probably an internal problem.

Is it solid or does it come on after the Receiver has been ON awhile.
It could be overheating.
Is the unit hot to the touch?
Is there a cooling device (fan)?
Is it stopped or clogged with dust?
Is there adequate ventilation around the unit for air to flow?
Clean any ventilation slots on the top and bottom of the unit.
Avoid stacking components that produce heat under an amplifier or receiver. Their heat rises. Also keep them away from other heat sources like like home heating vents and radiators.

Problem solid and NOT related to the speakers or heat: internal malfunction.

Let me know.

Posted on Apr 06, 2009

SOURCE: protection error in denon avr-3000

Hi,

Do you know what caused the protection shut down in the first place? Did you short your speaker wires even briefly?

You could try to Unplug the Unit for Few Minutes, say 30 minutes and then turn it back ON.Usually that would fix the issue.

If you are going into protect mode with no speaker attached,chances are that your output Ic is in need of replacement .This is the most likely cause of a protection error that you are experiencing.I am having a bit of difficulty in locating specific part numbers but feel confident that replacing outputs will remedy your concern.For further info and parts or authorized service locations in your area I suggest to contact mfg at www.usa.denon.com/ .Click on support or call(201)762-6500.I believe that they have a flat rate service and will give you an estimate.

Still, on the remote possibility that it is just a glitch caused by momentary power interruption or fluctuation, try to re-initialize the microprocessor, a hard reset (not unless this is what you were referring to as rebooted). The reset should force the AVR-3300 to revert back to factory defaults removing glitches, errors in settings & configurations, memory & presets as well as user preferences.

* turn OFF the unit using the POWER button;
* press and hold both SPEAKER A and SPEAKER B;
* without releasing the 2 buttons, press the POWER button;
* release the 2 buttons only when the display starts to flash;
* in the event of no display flashing, repeat the process.


Should the above be not corrective, then it would be a hardware fault and not just a glitch.


Let me know, if needed further assistance.

Hoe i helped you.

Thanks for using ' Fixya ' and have a nice day!!

Posted on Jan 13, 2010